Seal for metal straps



Nov.'20, 1934. F. P. PRINDLE SEAL FOR METAL STRAPS Filed NOV. 25, 1932 Patented Nov. 20, 1934 UNITED STATES PATENT. OFFICE SEAL FOR METAL STRAPS Application November 25, 1932, Serial No. 644,157

'7 Claims.

This invention relates toseals for securing together the ends of metal straps such, for example, as are applied to shipping boxes, and has particular reference to a seal of the type having a sleeve about the overlapped strap ends, the sleeve and enclosed strap ends having marginal tongues so as to provide interlocking shouldersbetween the seal and the strap ends. It is the usual practice in seals of this kind to provide, at each side of the sleeve, a relatively wide tongue by making two well defined slits and bending the metal of the sleeve and the strap ends between these slits at an angle to the general plane of the seal, the resultant tongue being as wide as the notch between the slits. With this old arrangement, it is possible, by applying considerable pulling strains to the strap, to draw the tongues back into their original planes, with the result that the strap ends may be pulled from the sleeve and the seal thus broken. Also, owing to the fact that the strap ends are sheared at their margins and at the outer sides of the tongues (that is, at that side of the tongue adjacent or towards the end of the sleeve) the strap is very materially .weakened at the localities where it is most likely to break or tear.

The aim ofthe present invention is the provision of certain improvements in seals of this sort whereby the above and other objections and inefliciencies of seals as previously formed are overcome, and particularly to provide an improved and effective seal having increased holding power and wherein a very high percentage of the normal strength of the strap is retained.

In accordance with the present invention, there is preferably formed two relatively narrow and short tongues at each side of the sleeve, I having found that two tongues of this nature may be formed more easily than a single wide tongue and that two tongues have greater holding power than a single tongue. The tongues in my improved seal are so made that at their outer or free ends they are somewhat wider than the notches from which they have been bent, thus preventing the tongues from being drawn back into their original planes when pulling strains are exerted on the strap. Also, in accordance with the present invention, each tongue is so formed that at the outer side thereof the strap ends are not sheared but are merely bent up so as to provide interlocking shoulders between the strap ends and the sleeve, while at the other or inner side of each tongue the walls of the sleeve and the strap ends are sheared so as to provide abrupt interlocking shoulders, the advantage of this arrangement being that the full holding power of the tongues is employed to prevent the strap ends I from slipping from the sleeve under strains while,

at the same time, substantially thefull strength of the strap is retained along the transverse lines coincident to the outer side edges of the tongues. This latter feature eliminates cuts at the marginal edges of the strap at those points where the strap is most likely to break or tear. In short, I provide a more effective and stronger seal wherein the breaking point of the strap is materially higher than in seals of like nature heretofore employed. My improved seal may be used in connection with box strapping of various sizes.

Other. objects will be in part obvious, and in part pointed out more indetail hereinafter.

The invention accordingly consistsin the features of construction, combination of elements and arrangement of parts which will be exempli fied in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawing, wherein is shown, for illustrative purposes, one embodiment which the present invention may take,

Fig. .1 is a top plan view of the formed seal;

Fig. 2 is an edge view thereof;

Fig. 3 is a transverse sectional view taken substantially on line 33 of Fig. 1;

Fig; 4 is an end view of the seal;

' Figs. 5, 6, and '7 show the stepsfor forming the seal, together with the anvil of the tool which may be employed to this'end, these views being more or less diagrammatic;

Fig. 8 is a more or less diagrammatic view in side elevation of the anvil and sealing jaw with the sleeve therebetween;

Fig. 9 is a longitudinal sectional view taken through one edge of the sleeve, this, view being taken-generally on line 99 of Fig. 4 and being in some particulars somewhat exaggerated; and

Fig. 10 is a perspective View of the formed seal, inverted from the position shown in Fig. 1.

Referring to the drawing,'A and A" designate generally the ends of a strap, and B the sleeve enclosing the overlapped strap ends. C is an anvil, and D is a sealing jaw of a tool which may be employed for forming the seal, it being understood that any suitable tool may be employed, and therefore these two elements are shown more or less diagrammatically for illustrative purposes The sealing member B may be given the initial shape shown in Fig.5 and may be folded or'bent a generally U-shaped portion 11 constituting a" part of the sleeve, and interposed portions 12 and 13 of the respective strap ends. Each tongue is so formed that the upper and bottom walls of the sleeve and the strap ends are sheared at the inner side of the tongue, that is, along the line 14, so as to provide abrupt interlocking shoulders along that line. The tongues at their outer side edges 14' are only partially sheared, so to speak, so that the strap ends along these edges are given unbroken and. "somewhat rounded shoulders 15. The lower wall of the U-shaped portion 11 at the outside edge 14' of the tongue is sheared only at the extreme end of the tongue leaving behind that extreme end a drawn out somewhat rounded portion 16 forming a shoulder complementary to the shoulders 15. The outside edge of the notch from which the tongue isformed is, at its outer end, inclined or rounded towards the end of the sleeve, as at 1'7, so that the outer end of the tongue is wider than the outer end of the notch, as will be seen most clearly from Fig. 2. This round or inclined portion 1'7 constitutes a shoulder underlying the tongue.

In Figs. 5 to 8, I have shown forillustrative purposes, a tool which may be used to form the above described seal. This tool may have an anvil C-with relatively thin male die members or cutters'25, the opposed faces 26 of which are relatively inclined. The tool may also have a sealing jaw D provided with grooves 27, one for each cutter. Each groove has along its inside edge a right angled cutting edge 28 with which the right angled cutting edge of one of the cutters 25 is adapted to cooperate so as to makethe shear at the inside edge of the tongue. The other or outside edge of each notch is rounded,'as at 29.

From the foregoing description, taken in connection with the accompanying drawing, it will be seen that the tongues being relatively narrow require but little power to form them, which is especially important when sealing wide and heavy box straps. The angle of the tongues is such that the normal efiective width of the strap is reduced as little as possible while at the same time a good interlock between'the strap ends and the seal is obtained. Due to the rounded edges 29 on the sealing member D, the tongues are partway sheared at their outer side edges 14 and then broken the rest of the way, so that the outer end of the tongueis wider than the notch from which I it has been bent. This means that when a pulling force is exerted on the strap ends,the tongues are prevented from being pulled back into the notches, even though the tongues are relatively narrow. It will alsobe noted that the strap endsv been broken at their margins along this line, and these shears give likely starting points for the strap to break all the way across.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing fromthe scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. A seal for metal straps comprising overlapping strap ends and a metal sleeve encircling the same, said seal having at each side of the sleeve a pair of tongues each formed of aU-shaped portion of the sleeve'and interposed portions of the strap ends, the metal of the sleeve and the strap ends being sheared at the inside edges of the tongues, the strap portions at the outside edges of the tongues being unbroken and having shoulders, said sleeve having shoulders corresponding to and interlocking with said shoulders on said strap portions.

2. A seal for metal straps comprising overlapping strap ends and a flat metal sleeve encircling the same; said seal having at each marginal edge a pair of narrow tongues angularly disposed to the plane of the sleeve, the tongues along one side being respectively opposite the tongues of the other side, each tongue being formed of a U-shaped portion of the sleeve and interposed portions of the strap ends, the metal of the sleeve and the strap ends being sheared at the inside edges of the tongues, the strap portions at the outside edges of the tongues being unbroken and having shoulders, said sleeve having shoulders corresponding to and interlocking with said shoulders on said strap portions.

3. A seal for metal straps comprising overlapping strap endsand a metal sleeve encircling the same, said seal having at each marginal edge a pair of tongues disposed at an angle to the plane of the sleeve, each tongue being formed 1 5 of a U-shaped portion of the sleeve and interposed portions of the strap ends, there being abrupt interlocking shoulders between the sleeve and the strap ends at the inside edge of each ofthe tongues; the strap ends at the outside edges of the tongues being unbroken and having shoulders arranged at an angle to the plane of the strap ends, said sleeve at the outside edges of the tongues having shoulders'cooperating with said last mentioned shoulders to prevent the strap ends from being pulled from the sleeve.

4. A seal for metal strapscomprising'overlapping strap ends and a flat metal sleeve encircling the same, there being tongues in the marginal edges of the seal and notches from which said tongues are bent, each tongue comprising .a U'-shaped portion of the. sleeve and interposed. portions of the strap ends, said tongues being disposed at an angle to the plane of the sleeve and each tongue havinga portion of greater width than the width ofi'the corre-.' sponding portion of the notch whereby the tongue is held against moving back into the notch when. a pulling force is exerted on the, strap. l. I -l50 A seal for metal straps comprising overlapping strap ends and a flat metal sleeve encircling the same, there being tongues in the marginal edges of the seal disposed at an angle to the plane of the sleeve, there also being in the marginal edges of the seal notches from which said tongues are bent each tongue comprising a U-shaped portion of the sleeve and interposed portions of the strap ends, each of said notches having a side wall with a shoulder underlying a portion of a tongue whereby the tongue is held against moving back into the notch when a pulling force is exerted on the strap.

6. A seal for metal straps comprising overlapping strap ends and a flat metal sleeve encircling the same, said seal having in its marginal edges sheared tongues each comprising a U-shaped portion of the sleeve and interposed portions of the strap ends, said tongues being disposed at an angle to the sleeves, the strap ends to one side of each tongue being sheared and to the other side of each tongue being unbroken and having shoulders, a portion of each tongue being of greater width than that of the notch from which the tongue is bent, thereby to prevent the tongues from being drawn back into the notches.

'7. A seal for metal straps comprising overlapping strap ends and a metal sleeve encircling the same, said seal having at each side of the sleeve a pair of tongues each formed of a U- shaped portion of the sleeve and interposed portions of the strap ends, the metal of the sleeve and the strap ends being sheared at the inside edges of the tongues, the strap portions at the outside edges of the tongues being unbroken and having shoulders interlocking with shoulders on the sleeve, said tongues at their outer ends being of greater width than that of the notches from which they are formed.

FRANK P. PRINDLE. 

